They attacked Loofah, Doofah and Foobie while Littlefoot, Cera, Ducky,Petrie and Spike were looking for water. They cornered the three yellow bellies but the others (who were standing on a path above) buried them with rocks.
However, while they were meeting up with the herd of yellow bellies the Baryonyxes got out. They track them down on a mountain where they started attacking the herd. The four Sharptooth started backing away when the yellow bellies all sang and bounced on their bellies at the same time and then the ledge they were on broke off the rest of the plateau. They presumably died of the fall.